Badminton Racket Shaft Stiffness: Why Brand Labels Differ

Last checked: August 2026 · Written by the player-led team at Badminton House

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Why one brand's stiff can be another's medium

No badminton authority defines shaft stiffness at all. BWF's Laws of Badminton cap a racket's frame at 680 mm by 230 mm and describe the shaft only as the part connecting handle to head, so "stiff," "medium" and every number printed on a shaft are entirely manufacturer inventions with no shared reference point.

The Laws of Badminton, Law 4.1 regulates a racket's overall size and names its parts only by what they do. It caps the frame at 680 mm long and 230 mm wide and defines the shaft as simply the part connecting the handle to the head. Bend, flex and stiffness never appear in the section.

Into that gap, the major manufacturers each built an internal ranking instead of adopting a shared one. A label only has to make sense against that same brand's other rackets: a company can call a shaft "medium" as long as it sits between that company's own softer and firmer models. Nothing requires the result to land in the same place as a rival's "medium," and nothing checks that it does.

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What Yonex, Victor and Li-Ning actually print

Three of badminton's largest racket makers use three different systems. Yonex and Li-Ning each print a word from their own ladder, Victor prints a number from one to ten, and none of the three discloses the physical bend, in degrees or millimetres, that any single grade represents.

On current Yonex spec sheets, Shaft Flex is printed as a single word with no number attached. Live listings run from Hi-Flex through Medium to Extra Stiff; the ASTROX 88S PRO is graded Stiff, for example. The same table prints Length as its own separate row, stated as an offset such as "5 mm longer" rather than a millimetre figure, so two Yonex rackets that share a flex word are not guaranteed to share a length.

Victor is the outlier: instead of a word, its product pages carry a Response Indicator, a 1-to-10 handling number. Victor's own buying guide explains the range. A rating of 1 to 3 is more flexible and suits children, 4 to 7 is average and works for beginners and advanced players alike, and 8 to 10 is stiffer and hits harder but can feel shaky. The same guide adds that the number reflects the frame, shaft and handle together, describing a finished racket rather than a raw shaft sample.

Li-Ning runs its own word ladder again, from Ultra Flex through Flexible and Mid Flex to Stiff. Its racket buying guide pairs the flexible end with juniors, defensive players and beginners still building technique, and the stiff end with advanced, attacking players who want tighter control. That vocabulary has no fixed relationship to Yonex's words or Victor's numbers; Li-Ning built it to describe its own catalogue.

Line the three systems up by rough position and a pattern appears: each brand runs softer to firmer, and each brand's middle targets a similar kind of player. Read the table below as three separate ladders shown side by side, never as a single scale with three sets of labels, because no brand has published the physical bend behind any of its grades.

A Victor 6 and a Yonex Medium occupy roughly the same rough position on this layout. Whether they bend the same amount in your hand is exactly what no label can tell you, which is the job the next section takes over.

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Feel it in your hands: a two-racket bend test

A five-minute side-by-side test tells you more than any printed grade. Hold the racket you already trust next to the one you are considering, grip both at the same point on the handle, press both heads against the same fixed edge with equal force, and watch which shaft bends further.

1. Match your grip point. Hold both handles at the same spot on the grip so neither racket gets a leverage advantage from being held further up or down.
2. Anchor both heads the same way. Rest both racket heads against the same table edge, wall corner, or a second person's flat palm, at the same angle.
3. Push with matched, moderate force. Press the handles down by the same modest amount each time, comparing bend at one matched load rather than pushing to the limit.
4. Watch the shaft, not the head. The racket whose shaft curves more before the head stops moving is the more flexible of the two, whatever either label says.

Do this with a racket you already know on court and the comparison stops being abstract. A new frame that bends noticeably less than your current one under the same push should feel firmer in a rally, whatever the catalogue calls both of them; a frame that bends more should feel softer. A printed grade only has to make sense inside one brand's own range, and length and handle construction shift how an assembled racket behaves, so this comparison accounts for the whole racket rather than one row on a spec sheet.

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Why two "stiff" rackets can still feel different

A shared flex word does not guarantee a shared length or handle build. Yonex prints racket length as a field separate from shaft flex, and Victor states plainly that a racket's overall stiffness comes from the frame, shaft and handle together, not the shaft alone.

Yonex's own catalogue shows this clearly, because the two fields sit right next to each other on the spec sheet. The ASTROX 88S PRO is graded Stiff at "5 mm longer" than Yonex's standard length; the NANOFLARE 1000 Z is graded Extra Stiff at "10 mm longer." Both sit at the firm end of Yonex's word scale and both run longer than standard, but by different amounts, confirming that the flex word and the length are two separate dials on the same racket. For the fuller reach-versus-manoeuvrability trade-off a longer shaft brings, see our guide to shaft diameter and length.

Victor makes a related point from the construction side. Its buying guide states that a racket's flexibility and stiffness come from the frame, shaft and handle design and material working together, which is why its 1-to-10 number describes the finished racket rather than a shaft sample on its own. Change the handle's core, the cap where shaft meets head, or the overall length, and an otherwise identical shaft can play differently once it is assembled, while the printed grade stays exactly where it was.

A printed grade is still a useful starting filter. It just answers a narrower question than most buyers assume, which is why the bend test above and your own swing carry more weight than the word on the shaft.

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Matching stiffness to your swing, and switching brands

Your own rally tells you more than any label. A shaft that feels harsh, unforgiving or short on power on repeated clears is probably too firm for your swing right now; one that feels delayed, wobbly or slow to recover on fast exchanges is probably too soft, regardless of what word or number is printed on it.

On the firm side, watch for clears that fall short of the back line even when your technique feels right, a smash that feels flat instead of heavy, or arm fatigue after a normal session. On the soft side, watch for blocks and drives that arrive late, a racket that still feels like it is catching up on your fastest exchanges, or smashes that lose their steep angle the harder you swing. Either pattern points to a swing-speed mismatch rather than a faulty racket.

Switching brands is where labels cause the most confusion, because you change the word or number and the racket underneath it at the same time. Li-Ning's own guide is direct about the risk: do not suddenly switch from one end of a flex range to the other after years on one type, warning of the injury risk that comes with a sudden change in how much the racket cushions and transmits your swing. Bend-test the new racket against your current one first, move one step at a time along whichever brand's own ladder you are buying into, and give your arm a few sessions before you judge the change.